Many vehicles, such as utility vehicles (also known as pickup trucks), have an open deck bounded at the perimeter with walls and a tailgate. In use, this deck is covered by canvas or soft vinyl-coated fabric secured (via snap lock fastenings, elastic loops, or the like) about the upper edges of the walls surrounding the deck. These types of covers have a problem in that they can collect rainwater at their center, causing them to sag in the middle. Furthermore, over time, the appearance of the cover degrades through prolonged exposure to incremental weather and sunlight.
As an alternative, many manufacturers of utility vehicles, or manufacturers of accessories made to the original equipment manufacturer (OEM) standards, provide rigid covers that cover the truck bed. These rigid covers do not have the sagging problem that can be observed in soft covers. While rigid covers made from a single shell are known, these have to be sufficiently over-engineered to withstand the stresses of use, particularly when items such as tools and construction materials are placed on top of the cover, as is sometimes known to occur. This over-engineering of single shell rigid covers has a consequent effect on their portability and expense to the consumer.
More commonly, rigid covers are typically formed from molded fiberglass or plastic material and are formed from two shells—one inner shell and one outer shell. The inner shell, which faces the deck of the utility vehicle with which it is being used, helps provide support for the outer shell, which faces upwards, and thus is exposed to the weather. This type of structure is preferred to ensure that the overall structural integrity of the cover is not compromised. Furthermore, the use of molded fiberglass or plastic material gives the user greater control of the overall appearance of the cover. Users can select a cover that better complements the color or shape of their vehicle. Furthermore, the use of these materials, as opposed to canvas or vinyl-coated fabric, also means that the cover retains its appearance for a longer period of time when exposed to incremental weather and sunlight.
An example of such a cover is described in U.S. Pat. No. 6,547,310. This patent generally discusses a cover that is formed from a textured outer layer, vacuum formed to a specific shape, with an inner support layer that includes a number of support ribs. Both the outer and inner layers are formed from plastic acrylonitrile butadiene styrene (ABS) sheets.
However, these two- or dual shell rigid covers have some problems. One significant problem is that of thermal expansion of the respective shells when exposed to extreme temperatures. When the inner and outer shells expand or contract at different rates, this stresses the joins between the two. Over time, the bonds and connectors linking the inner and outer shell may deteriorate and break down. As the inner shell is necessary for support of the outer shell, the overall structural integrity of the rigid cover is compromised and it may need to be repaired or replaced.
A further disadvantage of dual shell covers is that if an aftermarket OEM accessory such as a sports bar is to be used, this greatly complicates installation. The sports bar is not typically fitted to the cover itself as doing so can inhibit the range of motion when it is being opened. Instead, rigid covers intended for use with sport bars come in multiple parts; a main body, which is the portion that is raised and lowered, and two smaller parts for either side of the deck. The latter parts are fixed and do not tilt, and the sports bar can be secured to these parts. This arrangement is more expensive to manufacture and complicates installation to the utility vehicle.
Accordingly, it is an object of some embodiments of the present invention to address the foregoing problems or at least to provide the public with a useful choice. Further aspects and advantages of some embodiments of the present invention will become apparent from the ensuing description, which is given by way of example only.